I use a thermoelectric cooler and a radiator inside the cabinet for cooling.
The TEM cools the water that flows through the radiator. I have a PWM controlling fan speed.
I use a PID controller to monitor and control cabinet temperature. I have an ultrasonic humidifier hooked up to an Auber humidistat. The humidistat also controls a purge fan that purges moist air out of the cabinet through 2 one way valves.
If you will be operating in humid conditions, you will need a dehumidification scheme.
JC